Refractory brick structure



4 Sheets-Sheet 1 Filed Nov. 3, 1938 July 14, 1942. R. P. HEUERREFRACTORY BRICK STRUCTURE Filed Nov. 3, 1958 4 Sheets-Sheet 2 July 14,1942. R. P. HEU'ER -.2,2s9,911

REFRACTORY BRICK STRUCTURE Filed Nov. 3, 1938 4 Sheets-Sheet s PatentedJuly 14, 1942 REFRACTORY BRICK STRUCTURE Russell P. Heuer, Bryn Mawr,,Pa., asslgnor to General Refractories Company, a. corporation ofPennsylvania Application November 3, 1938, SerialNo. 238,505

15 Claims.

The invention relates basic brick provided with spacer plates andintended for use in basic suspended furnace roofs or walls and also tothe suspended furnace roofs and walls produced.

The present application is a continuation in part of my U. S.application Serial No. 198,426, filed March 28, 1938, for Refractorybrick process, now Patent 2,247,376.

A further purpose is toconstruct a-fwall from brick of the presentinvention, desirably having an oxidizable metallic spacer plate moldedas part of the brick substantially covering one horizontal face only andparts of two adjoining I lateral faces.

A purpose of the invention is to mold brick by V direct pressure againsta lateral face and, concurrently with the molding, fasten oxidizablemetallicspacers on a lateral face or faces of the brick.

A further purpose is to apply to a brick a U- shaped oxidizable metallicspacer which covers the preponderant part of one face and parts of twoother adjoining faces of the brick, embedding interlocking projectionsor tabs from the spacer in the brick as the'brick is molded A furtherpurpose is longitudinally to weaken a spacer plate which is in contactwith one of the dies of a brick molding press to permit lateral pressureadjustment and, where a slot is used, to allow the escape of air fromthe brick during molding.

A further purpose is to form a brick with substantial parts of threelateral faces covered by an oxidizable metallic spacer plate appliedduring molding, and to cover the fourth side by an oxidizable metallicspacer plate applied subsequent to molding and desirably held in placeby resilient prongs engaging the ends of the brick.

A further purpose is to slot a U-shaped oxidizable metallic spacer platelongitudinally of the.

base of the U, leaving connecting prongs, to divert the connectingprongs into the interior of the U and to embed the connecting prongs inthe brick during molding. A further purpose is to hold a U-shaped ox-'idizable metallic spacer plate by embedding projections from. the sidesof the U in the brick during molding.

A further purpose is to build up a basic suspended furnace roof byalternately hanging oxidizable metal-clad basic refractory bricks andunclad basic refractory bricks, the clad bricks preferably havingsubstantial portions of all four sides covered by spacer plates.

A further purpose is to employ, in a basic suspended furnace roof,bricks having spacer plates on all four sides alternately with taperedbricks free from spacer plates, the taper allowing for growth of thespacer plates near the hot ends clue to oxidation while protectingagainst excessive lateral pressures.

A further purpose is to employ an oxidizable metallic spacer plate onahorizontal face of a wall brick while leaving portions of vertical facesof adjoining wall bricks unprovided with oxidizable metallic spacerplates and therefore better equipped to impede melting out of the spacerplate.

Further purposes appear in the specification and in the claims.

The drawings illustrate a few of the many possible embodiments of theinvention, the forms shown being selected from the standpoints ofconvenience in illustration and satisfactory explanation of theprinciples involved.

Figures 1, 2 and 3 are respectively top plan. front elevation and sideelevation views of a U-shaped spacer plate as employed in the presentinvention.

Figures 4, 5 and 6 are respectively top plan, front elevation and sideelevation views of a spacer plate which may be applied to the brickafter molding.

Figure 7 is a perspective view of a completely molded basic suspendedroof brick of the invention.

Figures 8, 9 and 10 are respectively top plan, front elevation, and sideelevation views of a variant form of U-shaped spacer plate.

Figures 11, 12 and 13 are respectively top plan, front elevation andside elevation views of a U- shaped spacer plate which may be used withthe spacer plate of Figures 8, 9 and 10.

Figure 14 is a perspective view of a completed 7 brick using the spacerplates of Figures 8 to 13.

Figure 15 is a perspective view of a tapered unclad brick whichdesirably alternates with the brick of Figures 7 or 14 in the suspendedroof.

Figure 16 is a top plan view of a basic suspended furnace roof usingbricks of the presentin'vention, omitting the hangers for clear Figure18 corresponds to Figure 17 and shows the spacer plates after they haveoxidized'some distance back of the hot face.

Figure 19 is a perspective view of a wall brick embody! the presentinvention.

Figures 20 and 21 are alternative wall constructions using the wallbrick of Figure 19.

In the drawings like numerals parts.

As explained in Russell Pearce Heuer U. S. Patent No. 2,154,818, grantedApril 18, 1939, for Suspended furnace roof, very effective suspendedfurnace roofs can be obtained by hanging basic refractory bricks side byoxidizable metallic spacer plates between the bricks. The spacersoxidize near the hot face of the roof and ordinarily for some distanceback of the hot face. As the oxide occupies a greater volume than theoriginal'spacer metal, growth of the spacers results from the oxidationand the spacer oxide rigidly unites with the adjoining faces of thebricks, exerts a mild lateral pressure on the bricks, and seals thejoints between the bricks. Whereas before growth the bricks and thespacers are usually relatively loosely associated and the individualbricks and spacers are capable of adjusting their relative positions asthe furnace heats up, the oxidation of the spacers causes integration ofthe roof or of large units of the roof. Y

In construction of basic suspended furnace roofs of the type referredto, certain dimculties have been encountered. The separate operation ofapplying the individual spacer plates to the refer to like side andinterspersing preformed bricks during construction of the roof hasresulted in increased labor cost of building the roof.

In the previously constructions there has not always been closeconformity between the brick and the spacer plate, due in some cases toirregularities in the brick and in other cases to unintentional bendingof the spacer plate prior to or during assembly of the roof.

On an experimental basis, the present inventor has attempted to attachthe plates physically to the premolded brick by adhesive or byresiliently gripping the brick by the plate. This has not in all casesbeen fully satisfactory because in the assembly of the roof there havebeen points where the spacer plate on one brick contacts the spacerplate of an adjoining brick instead of being in contact with the lateralface of the adjoining brick. Thus after oxidation, in order to integratethe roof, there must be not only coalescence between the brick and theplatebut also welding or coalescence between two plates, The extraspacer plate thickness increases the danger that the plates will meltout rather than oxidize, since in many of the furnaces employing theroofs of the present invention such as open hearth steel furnaces, theoperating temperature of the furnace is above the melting point of theiron or steel spacers. Furthermore separate application of many spacerplates to premolded bricks is cumbersome, and not always very effective.

In accordance with the present invention, the spacer plate or plateswill not in most cases be applied to a preformed or premolded brick asin Patent No. 2,154,813 aforesaid, but the spacer plate or plates willbe formed as part of the brick at the time of molding the brick.Applicant will not, however, pack in the refractory through the ends ofa closed casing as'in Maccallum U. S. Patent No. 1,106,725, grantedAugust 11, 1914, for Furnace wall construction. This patent discloses abrick'not suitable for and never applied to suspended furnace roofs.

In accordance with the present invention, the spacer plate acts with thedie for the purpose of molding the brick, and is secured to the brickduring molding as by suitable interlocking means embedded in the brick.

While the best use of the invention will probably be in basic suspendedfurnace roofs, certain aspects of the invention are applicable infurnace walls, as later explained.

This method of molding by applying pressure through the spacer plateitself assures absence of voids between the spacer plate and the brick,gives uniform pressure distribution, produces a smooth brick surface andvery firmly unites the spacer plate to the brick.

The process of making the brick of the present invention is described inmy U. S. Patent No. 2,247,376, granted July 1, 1941, for Refractorybrick process, which is incorporated herein by reference.

The brick mix employed may, for example, be magnesia as described inHeuer application Serial No. 707,084 aforesaid, or as described inRussell PearceHeuer U. S. Patent No. 1,859,512, granted May 24, 1932,for Refractory and method of making it, or in U. S. Patent No.1,992,482, granted February 26, 1935, for High-pressure brick containingmagnesia and process of making the same. On the other hand, a chromebrick mix may be employed as described in Russell Pearce Heuer U. S.Patent No. 1,992,483, granted February 26, 1935, for High-pressurechrome refractory. Chrome-magnesia brick may be employed 'as describedin Russell Pearce Heuer U. S. Patent No. 2,087,107, granted July 13,1937, for Chrome magnesia refractory and method or Patent No. 2,155,165,granted April 18, 1939, for Furnace roof. As the present invention isnot primarily concerned with the composition of the refractory mix,which is fully disclosed in the other applications referred to above,the disclosure of said prior applications and patents is incorporatedherein by reference and made a part hereof, and

will be found to disclose the preparation of the I brick mix, thesuitable molding pressure and other pertinent information.

Where the term brick is used herein, it .will be understood that anysuitable block or other shape is intended, provided with any specialcontour desired to engage the particular type of hanger.

A space: plate 34 (Figures 1 to 3) of generally U-shape has arms 31 anda base 38 of the U. The arms 31 are desirably not as long as the widthof the side of the brick, so that a portion 39 of the side of the brickis not covered by the spacer plate (Figure 7).

Projections or tabs 40 punched out and bent inwardly from the spacerplate are embedded in the brick during molding.

The hook engaging depression 42 and hanger slot 43 are also formingduringmolding.

Figures 1 to 4 show in greater detail the U- shaped spacer plate ofFigures 1 to 4. This spacer plate of Figures 1, 2 and 3 is shown appliedto the brick 50 in Figure 7." The base 38 of the U preferably is appliedto the rear lateral face of the brick 50, with the arms 91 of the Uapplied to the side faces of the brick. The interlocking tabs 40 punchedout and bent inwardly from the spacer plate are embedded in theszidefaces .of the brick as indicated in Figure As molded, the brick ofFigure 7 hasa front face unprovided with a spacer plate. This is Allconnecting the sides of the covered by a spacer plate ll shown inFigures 4 to 6 having resilient prongs at I! at the top and II a thebottom which engage over the upper and ower end faces of the brick(Figure 7). A slot It near the upper end of the spacer plate BI is cutas shown to. admit the hanger to the hanger recess, later described. Thefeature of the resilient engagement of the prongs and 53 with the brickis claimed in Patent No. 2,155,165 aforesaid.

The preferable construction of suspendedfurnace roof brick is thatindicated in Figure 14. The rear spacer plate 34' for this brick isshown in Figures 8 to 10, in which the base it of the U engages the rearface of the brick it and the arms 37' of the U engage portions of thesides of the brick as shown in Figure 14. Interlocking projections llformed from the arms are embedded in the sides of the brick. In somecases the interlocking projections may extend generally horizontal whenthe brick is suspended as in the construction ofFigures 1 to 3, but itis usually preferred to have these interlocking projections extendvertically when the brick is suspended as shown in Figures 8 to 13. Thespacer plate 3|" contacting the front face of the brick it is shown inFigures 11 to 13. The base ll" of its U contacts the front face of thebrick and has the usual cut away portion for the hanger. The side arms31" of the U cover portions of the sides of the brick and havevertically extending interlocking projections 40' as shown in Figure 14,which are embedded in the sides of the brick. The interlockingprojections slot ll are'seen embedded in the front face of the brick.

The weakening of the base of the vU of the spacer plate. as shown inFigures 11 to 14, perassembled alternately with a brick Ill having nospacer plates, brick I and shown in Figure 15.- The may haveconventional uniform lateral faces, but it will preferably be tapered asillustrated from a maximum lateral dimension at the top to a minimumlateral dimension at the bottom. This taper allows for a certain growthout exerting excessive pressure.

a satisfactory taper is of the oxidized spacers near the hot ends with-The taper is been found that inch (0.079 centimeter) not of coursenecessary. It has against one another without danger that there will notbe suflicient space allowed for growth near the hot face of the roof,but when no taper is used. the workman should not press the bricks hardtogether laterally.

mits the spacer plate to adjust laterally during the molding operationand prevents kinking or bowing of the spacer plate, particularly the onewhich adjoins the movable die.

The preferred form of longitudinal weakening employs a slot 48 whichruns longitudinally through the base 38 of the U of the spacer plate34", being interrupted at intervals for the cross connections betweenthe two sides of the spacer plate. These -cross connections bentinwardly form the interlocking projections All". It will be understoodthat the width of the base 38" of the U in the spacer plate 34 isadjusted somewhat during molding by change in the width of the slot 48and by bending of the interlocking projections 40 The slot 48 alsoallows air to escape during molding, thus avoiding air entrapment. Thisfeature of air release through the slot 48 or some equivalent opening isparticularly important when using opposite spacer plates, as in Figure14. although not of the same importance, when a single spacer plate isco-molded with the brick as in Figure 7.

The arms 31' and I1 ofthe spacer plates 34' and 34* are preferablyshorter than the lateral dimensions of the side face of the brick, sothat when the brick is compressed, the arms cannot meet and causecrushing or bending, even though there may be some variations in thecharge of brick mix. Aline of refractory 41 is ordinarily exposed at theside of the brick.

The upper corner of the side arm of the U is preferably cut away as seenat in Figures 13 and 14 to avoid undulystressing the brick corner duringmolding.

The brick" of Figure 7 or 14 is preferably each encased brick I is frontside and back to back against an unencased The assembled roofconstruction is shown in Figures 16 to 18. These figures show bricks itof the type of Figure 14 alternating with bricks 50' of the type ofFigure I 6. It will be understood that the encased-bricks could be ofany other suitable yp for example, 7. Thus throughout the roof except atone edge to front, side to brick ll, so that there is no possibilitythat two thicknesses of spacer plates will intervene between the brickfaces at' any side.- The hangers I. are of course connected to the usualoverhead structure (not shown), pass through hanger slots 43 of anysuitable form, and have hooks $7 engaging in hanger recesses 42. Priorto oxidation of the spacers, the bricks are quite loose laterally, asshown in Figure 17, so that ordinarily an individual hanger and itsassociated bricks inight'be lifted out with the hand. This is anadvantageous feature, as the individual bricks are free to move andadjust during the initial heating up of the furnace and thus preventlocalized abnormal stresses upon individual bricks. It is only after theroof has been thoroughly heated at furnace temperature. and oxidationhas had its efl'e'ct, that the individual bricks are integratedtogether.

After the oxidation has its effect, the spacers near the hot facesswellor grow as shown at 58 in Figure '18, not only filling the spaceleft by the taper but exerting mild lateral pressure upon the bricks,forcing the spacer oxide into any recesses left in the bricks andcombining or coalescing with the brick material. In the case of brickscomprising magnesia, whether as the preponderant ingredient or as aminor constituent in a chrome brick, the spacer oxide appears to combinewith the magnesia to form magneslum ferrite which is quite refractoryand volume stable. A further important effect is that the growth of thespacers compensates for shrinkage of the brie This is of specialimportance where, as will usuallybe the case, the bricks are uniired andare subjected to furnace temperature for the first time when the furnaceis heated up.

The roof may or may not have lateral structural boundaries as explainedin prior patents, such as Nos. 2,154,813 and 2,155,165 aforesaid, sincethe effect of gravity upon adjacent bricks will tend to maintain themvertical.

a brick which is 3% x4' that of Figure cover at least portions of. twoother lateral faces brick having lateral faces and the brick, the brickmaking a molded union with the tabs. I

5. A basic refractory brick having lateral faces, a U-shaped oxidizablemetallic spacer plate having a base whichcovers the'preponderant part ofone lateral face of the. brick and arms which of the brick, the spacerplate being in molded conformity with the brick, and tabs bent inwardlyfrom the arms of the U-shaped spacer plate and making a molded'union 6.A basic refractory brick having lateral faces and a recess in one facenear the upper end for engaging, a hanger and a U-shaped oxidizablemetallic; spacer covering, the preponderant part of one lateral face andat least parts of each of two other lateral faces, the spacer platebeing in molded conformity with the brick, and having interlockingprojections embedded in the brick, the brick making a molded union withthe projections.

7. A basic refractory brick having lateral faces and apair of U-shapedoxidlzable metallic spacer plates each covering the preponderant part ofone lateral face and at least a part of each of the two other lateralfaces of the same brick, the spacer plates being in molded conformitywith the brick, and each spacer plate making molded union with thebrick.

4 8. A basic refractor brick having lateral faces,

a pair of U-shaped oxidizable metallic spacer plates, each having a basecovering'the preponderant part of one lateral face and each'having armswhich cover at least parts of two other lateral faces of the same brick,the spacer plates being in molded conformity with the brick, and

tabs bent" inwardly from embedded in the brick, union with the tabs. 9.A basic refractory brick having lateral faces, a pair of U-shapedoxidizable metallic spacer plates, each having a base covering thepreponderant part of one lateral face and each having arms which coverat least parts of two other lateral faces of the same brick, the spacerplates the spacer plates and' being in molded conformity with the brick,and

tabs bent inwardly from the arms of the spacer plates and embedded inthe brick, the brick making a molded union with the tabs.

10. A suspended furnace roof basic refractory having a hanger recessnear 'the top of one lateral face, a U- shaped oxidizable metallicspacer platehaving with the brick.-

embedded in the brick and the brick making a molded ing a preponderantpart of one of the faces and 7 having a slot extending longitudinallyfor the major part of the length of the brick and means making moldedunion with the refractory for interlocking the spacer plate with thebrick.

12. A basic refractory brick having lateral faces, an oxidizablemetallic spacer covering the preponderant part of one of the lateralfaces and weakened longitudinally of the face and interlockingprojections from the spacer plate embedded in the brick by refractorymaking molded union with the projections.

13. A basic suspended refractory brick having lateral faces, a .U-shapedoxidizable metallic spacer having the base of the U covering thepreponderant part of one of the faces and the arms of the U covering atleast parts of other faces, interlocking projections from the arms ofthe U embedded in the brick and means for weakening the spacer platelongitudinally of the base of the U.

14. A basic suspended refractory brick having lateral faces, a U-shapedoxidizable metallic spacer having the base of'the 'U covering thepreponderant part of one of the faces and the arms of the U covering atleast parts of other faces, interlocking projections from the arms ofthe U embedded in the brick. means for weakening the spacer plateslongitudinally of the base of the U and interlocking projections alongthe 'line of weakening embedded in the brick and making moldedunion'with the brick.

15. A basic refractory brick comprising a r' densely compacted mass ofbasic refractory par- I ticles and a U-shaped oxidizable metallic spacer7 in molded conformity with the brick.

RUSSELL P. HEUER.

